Kindred Spirits on the Roof / Timeline

Here is a list of the most significant events in Kindred Spirits on the Roof. Be warned- all spoilers are unmarked

Pre-Game Events

Roughly 97 years prior to the start of the game, Sachi is born.
80 years prior to the start of the game, Sachi dies after falling from the school roof while saving the girl she loved. An enoki tree is planted in her memory.
Roughly 45 years prior to the start of the game, Megumi is born.
At some point between Sachi's death and Megumi coming to Shirojo, the school switches to white Sailor Fuku uniforms.
30 years prior to the start of the game, Megumi falls ill and dies. After dying, Megumi meets and falls in love with Sachi.
At some point after Megumi's death, Shirojo adopts its current uniform.
Roughly 25 years prior to the start of the game, Tsukuyo is born
Roughly 17 years prior to the start of the game, Miki, Miyu and Matsuri are born.
Roughly 16 years prior to the start of the game, Yuna, Ano, Umi, Sasa, Nena, Kiri, Youka and Aki are born.
Roughly 15 years prior to the start of the game, Hina and Seina are born.
Five years before the start of the game, Matsuri and Miyu become a couple.
Three years before the start of the game, Tsukuyo gets a job teaching at Shirojo.
Two years before the start of the game, Miki, Miyu and Matsuri begin high school. In the same year, Yuna overhears her cooking club members talking about how they resent her.
One year before the start of the game, Yuna, Ano, Umi, Sasa, Nena, Kiri, Youka and Aki begin high school. At some point during this time, Yuna meets and befriends Ano.

April

On April 4, Hina starts school at Shirojo in the chronologically first playable scene.
On April 10, Seina gets lost and meets Miki for the first time.
On April 23, Seina writes a love letter to Miki but fails to deliver it.

May

The Golden Week holidays are held at the start of the month.
On May 7, the game begins. Yuna, having lunch on the roof by herself, meets Sachi and Megumi, who realize she can hear them. They convince her to become their "yuri cupid," and she reluctantly agrees, creating an opportunity for Seina to drop her love letter in Miki's bag.
On May 8, Yuna, after some thought, tentatively agrees to help the kindred spirits as their "yuri cupid."
On May 10, Miki responds to Seina's love letter, saying she doesn't return her feelings but they can start out as friends.
On May 18, Yuna and the kindred spirits start to investigate the broadcasting trio- Umi, Sasa and Nena- and find out who loves whom.
On May 21, Yuna and the kindred spirits, who have been observing the broadcast trio for a while, realize that Sasa is in love with Umi.
On May 31, Seina, with help from Yuna and Sachi, finds a "hideout" where she and Miki can spend time together without any interruptions.

June

On June 8, Kiri realizes that she is a lesbian and in love with her teacher Tsukuyo, a realization that immediately makes things awkward between them.
On June 15, Kiri, who has been avoiding Tsukuyo for about a week, tries running away from her, but Hina catches her. She talks with Tsukuyo and confesses to her, but Tsukuyo tries to convince Kiri that her feelings are a misunderstanding.
On June 18, Yuna meets with Youka for the first time in a long time and learns that Youka has a crush on Aki.
On June 21, Seina kisses Miki while the latter is asleep. Overwhelmed by guilt, Seina ends up avoiding Miki.
On June 22, Sasa goes home with Umi under the same umbrella and makes a Love Confession to Umi.
On June 30, the kindred spirits observe the anniversary of Megumi dying and being able to meet Sachi as a ghost.

July

On July 11, Miki forgives Seina for kissing her, and asks her to call her by her first name.
On July 12, Matsuri and Miyu recruit Yuna to cook for their training camp.
On July 17, Tsukuyo agrees to start a secret Teacher/Student Romance with Kiri.
On July 18, Umi and Sasa tell Nena about being in a relationship and offer to break up if their relationship ends up making things awkward, but Nena insists that they continue dating without worrying about her.

August

On August 8, the training camp, makeup classes and other summer activities at school begin.
On August 12, Umi and Sasa have Their First Time.
On August 14, Matsuri tries to get some affection from Miyu, but pushes her too far, resulting in a feud between the two. During the argument, Miyu angrily compares Matsuri to Hina, drawing the latter into their feud.

September

On September 19, Maki overhears some third-years badmouthing Miki, then loses her temper and attacks them. Miki brings her to her senses by calling her by her first name and giving her a Cooldown Hug.
On September 20, Seina receives a three-day suspension for fighting with the upperclassmen. She and Miki officially have a Relationship Upgrade, and they have Their First Time. Meanwhile, Sachi confesses her insecurities to Megumi and Yuna, both of whom accept her for who she is.
On September 21, the festival begins. Youka sings her song for Aki and gives her a Concert Kiss. Tsukuyo and Kiri receive an application for the math club, and have Their First Time at school.
On September 22, the second day of the festival, Miyu and Matsuri hold their date competition. Miyu takes Hina around the festival first, and Matsuri goes second, but Hina refuses to choose either of them, having realized that they love each other in spite of their bickering. Miyu and Matsuri make up and enjoy the festival together. Yuna, who is anxiously awaiting Hina's answer, is shocked when Hina makes a Love Confession to her.

October

On October 1, Youka is called into the faculty office for a lecture over kissing Aki and her chronic tardiness, but Tsukuyo and Aki stand up for her. Youka and Aki have Their First Time above the school gates.
On October 10, Matsuri and Miyu retire from the track team and have sex for the first time in a long time.
On October 20, Yuna has Ano over for a study session and learns that Ano can see but not hear the kindred spirits. Ano helps Yuna figure out how to answer Hina's confession.
On October 21, Yuna finally gives her answer to Hina's confession- she says yes.
On October 31, Yuna and Hina sneak into the school and allow Sachi and Megumi to possess them to have Their First Time. Finally fulfilled, Sachi and Megumi move on to the next life, and Yuna and Hina go home together. The credits roll.

November

On November 19, Yuna meets with her second- and first-year friends to discuss the upcoming Class Trip.
On November 22, Yuna and Hina have Their First Time without the ghosts possessing them. This is the last main story event and the chronologically last scene in the game.

Timeline / Kindred Spirits on the Roof